In this example, it asks which one of the following statements is true about radical polymerization? Impurities in the reaction mixture induce branching during polymerization. Here, we never mentioned that impurities are necessary for branching to occur during polymerization, so this is not true. Chain branching occurs through either an intermolecular or an intramolecular chain transfer reaction. This statement is true.

Remember, intermolecular reactions create long branches, while intramolecular reactions create short branches. Thus, this is true. Chain branching occurs if the termination step is slow. Once again, this is something we never mentioned when discussing branching, so this is not true. The initiator determines the amount of branching in the polymer chain.

Again, we never discussed initiators, such as peroxide, UV light, and heat, in terms of determining the amount of branching. We framed our discussion in terms of inter versus intramolecular reactions. So here, out of our four choices, only option B is correct.